The goal of the current proposal is to examine whether affective (i.e., emotional) reactivity to daily stressors is associated with allostatic loa, a multi-system index of physiological function that is associated with increased morbidity and mortality. This project will also determine whether older adults-by virtue of their less resilient physiological systems-are more adversely affected by daily stressors than are their younger counterparts. Finally, we will determine how history of chronic stressor exposure may influence the associations between affective reactivity to daily stressors, age, and allostatic load. Knowledge gained from the proposed research could reveal factors that place people at increased risk for debilitating physical health problems, potentially identifying an important pathway through which health disparities emerge in later life.